For engines C-Class is recommended to use multigrade oils. They are made on liquid seasonal oil (for example, 15W) and are therefore not necessarily be changed depending on the time of year (summer / winter). With the help of so-called oil thickening stabilized hot.
"W" in the designation SAE means that the oil is suitable for use in winter.
Legkotekuchih called multigrade oils which, together with other additives include ingredients for reducing the coefficient of friction in the engine. The basis for easy-flowing oil is so-called synthetic oil. When buying a thin-bodied oils should pay attention to the fact that it has been approved for use by Mercedes (designation on the container).
Neither fuel nor lubricant is impossible to add additional lubricants of any kind.